1. Field of the Invention This invention relates to a car body for railway rolling stock and, more particularly, a car body for high speed railway rolling stock.
A car body of the aforementioned type for railway rolling stock is described, for example, in pages 15-79 and 15-80 of a revised edition NO. 6 (1977) of the Handbook of Mechanical Engineering, wherein an underframe, a side construction, a roof construction and an end construction of the car body are assembled and combined with each other to form a car body. A load acting on the car body is supported by the underframe, side construction, roof construction and end construction, and the side construction is connected at its lower end to the underframe and at its upper end to the roof construction, respectively. Accordingly, the side construction described above may support almost of all the bending load acting against the car body, for example, a vertical load of a self-weight and passenger weight and a bending load generated by an end load of the car body.
In recent years, it is strongly requested to have a light weight car body in order to make a high speed railway rolling stock and to reduce power consumption. Additionally, to reduce the amount of labor required in manufacturing car bodies and also to reduce the required period of time for manufacturing the car body, it has been desirable to improve the car body construction as well as the manufacturing process of the car body.
A light-weight car body, is described on page 38 of Car Body Engineering No.176 (1986), wherein the car body is manufactured by a large-sized extruded member of aluminum, with each of the side construction, underframe and roof construction constituting the car body being connected by a plurality of extruded members longitudinally guided in the car body and connected to each other through a welding process. Accordingly, the number of component parts constituting the car body can be substantially decreased, and, it is also possible to reduce the labor and time required in the manufacturing operation of the car body. In this case, a specification of an outside plate and frame member which may act to form the car body is determined with reference to or dependence upon a load acting against the frame. In, for example, Railway Vehicle and Design Engineering, Ohkawa Publishing, 1980, pages 57-61, a calculation program through a finite element method is utilized to analyze a construction of a car body and to calculate a deformation of the car body or stress thereof. Then, a plate thickness and a shape of the outside plate and a frame member are determined in response to a stress acting on each of the portions in the car body. Additionally, the specification of the outside plate and frame member is generally preferably standardized as much as possible so as to reduce the number of types of outside plate and frame members required to manufacture the car body. A construction of each of the portions of the car body is determined in view of a bending stiffness of an entire car body which may substantially influence a riding comfort of the car. Further, a specification of each of the portions for constructing the car body is also determined with a view toward the bending stiffness of the entire car body.
In the prior art, the bending load acting against the car body has been the most substantiated in order to assure the bending stiffness of the entire car body. The entire car body has been constructed so as to have a substantially uniform bending stiffness by providing a common specification for the outside plate and frame member forming the car body.
In the prior art, a high shearing load is provided at the part where a body bolster for transmitting the entire load of the car body to a truck of the rolling stock is mounted. However, insufficient consideration has been given to the shearing load acting near the body bolster. For example, in the prior art, as a countermeasure a reinforcing member is partially mounted in order to prevent a buckling of the outside plate and a concentration of stress at the corners of a window frame generated under the shearing load. Thus, the construction of the outside plate and frame member of the car body or the structure of each of the portions of the car body has not been sufficiently determined in view of the shearing load. That is, a high shearing load acts near the body bolster and a high bending load may act at the central part of the car body. However, the structure of the prior art car body does not sufficiently support the shearing load and the bending load and does not have a light weight construction. Accordingly, the car body structure of the prior art does not necessarily provide an effective structure for improving the light weight construction of the car body.